• Nangkam, Lynda T.
• Johansson, Jens O. W.
• Luttongething, A. R. Bonity J.
• Vitoricayrezabal, Inigo
• Pallikara, Ioanna
• Whitehead, George F. S.
• Attfield, Martin
• Skelton, Jonathan M.

Abstract

<jats:title>Abstract</jats:title><jats:p>Controlling aspects of the μ<jats:sub>2</jats:sub>‐X<jats:sup>−</jats:sup> bridging anion in the metal–organic framework Ga‐MIL‐53 [GaX(bdc)] (X<jats:sup>−</jats:sup>=(OH)<jats:sup>−</jats:sup> or F<jats:sup>−</jats:sup>, bdc=1, 4‐benzenedicarboxylate) is shown to direct the temperature at which thermally induced breathing transitions of this framework occur. In situ single crystal X‐ray diffraction studies reveal that substituting 20 % of (OH)<jats:sup>−</jats:sup> in [Ga(OH)(bdc)] (<jats:bold>1</jats:bold>) for F<jats:sup>−</jats:sup> to produce [Ga(OH)<jats:sub>0.8</jats:sub>F<jats:sub>0.2</jats:sub>(bdc)] (<jats:bold>2</jats:bold>) stabilises the large pore (lp) form relative to the narrow pore (np) form, causing a well‐defined decrease in the onset of the lp to np transition at higher temperatures, and the adsorption/desorption of nitrogen at lower temperatures through np to lp to intermediate (int) pore transitions. These in situ diffraction studies have also yielded a more plausible crystal structure of the int‐[GaX(bdc)] ⋅ H<jats:sub>2</jats:sub>O phases and shown that increasing the heating rate to a flash heating regime can enable the int‐[GaX(bdc)] ⋅ H<jats:sub>2</jats:sub>O to lp‐[GaX(bdc)] transition to occur at a lower temperature than np‐[GaX(bdc)] via an unreported pathway.</jats:p>

Topics

• impedance spectroscopy
• pore
• single crystal
• phase
• Nitrogen
• Gallium